Fluid flow controller



Dec. 19; 1-944.

A. U. BRYANT FLUID FLOW CONTROLLER Filed Jan. 25, 1943 m 5 I. F

INVENTOR. Ausf/n U. Bryan) BY A TTORNE K the control of steam I Patented Decl 19, 1944 I FLUID FLOW CONTROLLER Austin U. Bryant, Berkeley, Calif., asslgnor to Fluid Control Engineering 00., a copartncrship consisting of Marvin H. Grove and Julia E. Grove, both of Piedmont, Calif.

. Application January 2 5, 1943, Serial No. 473,454

3 Claims.

This invention relates generally to fluid flow control devices and is adapted particularly for over a relatively wide pressure range. I

In Patent No. 2,264,306, there is disclosed a pressure reducing regulator capable of handling steam at relatively high pressures, and in which the diaphragm for operating the valve member is loaded by air or like gas under pressure. The space on the upper side of the diaphragm is connected to the outflow side of the regulator,'and a column of condensate is maintained over th diaphragm for its protection. Pumping action of the diaphragm, which tends to disrupt the column of condensate, is prevented by means of a baffiewhich extends in closeproximity with the lower side of the diaphragm. The baffie has a small orifice establishin communication between the confined space below the diaphragm and a larger space below the baflle whichcontains the loading gas under pressure. I

In many installations the regulator of Patent 2,264,306 gives satisfactory operation without undue heating or deterioration of the diaphragm. However under certain conditions it has been found that the diaphragm may be subject to serious overheating with rapid deterioration, par- I. ticularly wher a number of pipe bends or angles -may intervene between the regulator and the and which in particular tends to prevent undue oxidation at the higher temperatures.

Further objects of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying draw Referring to. the drawing:

Figure l is a side elevational view, incro'ss section, illustrating a steam regulator incorporating the present invention.

Figur 2 is anenlarged cross-sectional detail showing the fitting for introducing or bleeding off loading gas.

Figure 3 is an enlarged cross-sectional detail showing the fiow'restricting orifice.

Figure 4 is an enlarged detail showing the upper face of the wall underlying the diaphragm.

retains sleeve 15 in place.

flow passages n and I2. Within the body there is a bridge l3 provided with a seat ring I4. A

vertically movable valve member l6 cooperates with the seat I and is adapted to be moved between open and closed positions by the vertical operating rod 1 1.

Various means can be used to guide the valve member I6 but in this instance I provide a stationary sleeve l5 which is fitted within the opening l8 in the upper side of the valve body. Closure plate I 9 is clamped to the valve body, and Cylindrical plunger 2| is loosely fitted within the sleeve I5, and has its lower end attached to or formed integral with the valve member IS; A light compression spring 22 is interposed between plate l9 and plunger 2| and serves to urge this plunger together with valve member l6 downwardly towards the seat l4.

The lower end of the operating rod I'l connects with a flexible diaphragm 24. This diaphragm is formed of suitable resilient material, such as natural or synthetic rubber, preferably with some fabric reinforcement. While a planar diaphragm can be used it is desirable to employ one molded to spherical shape as illustrated. To form a connection with rod I! the upper side of the diaphragm is engaged by the dished diaphragm plate 26, the central portion of which has a socket-like button 21 to receive the lower end of rod 11.

The mounting for the diaphragm 24 is assembled from a number of parts including a plate 28 extending above the diaphragm, a dished plate 29 extending immediately below the diaphragm, a lower dome-like part 3|, and an upper domeshaped part 32. All of these parts can be conveniently formed of pressed sheet metal. Part 28 is annularly contoured, and has an inner portion 28a dished to conform with the curvature of the diaphragm. The flange portion 28b of this part The regulator illustrated in Figure 1 consists extends beyond the periphery of the diaphragm, and has an outer downturned rim 280. Part 3| has its upper end formed to provide the flange portion 3 la, and also the upturned rim 3lb which embraces the peripheral edge of the diaphragm.

Part 29 is dished or formed spherical shaped to conform with the contour of diaphragm 24, and has its peripheral edge portion seated within the rim 3l b, immediately below the peripheral edge portion of the diaphragm. Thepartsjust described are secured together by clamping bolts 33, which extend through the upper and lower clamping rings 34 and 36, and through circumferentially spaced openings in the flange portion 2817. When clamped together the peripheral edge ing downwardly through the parts 32 and 23, and

-secured to the same as by means oi. welding,

passage 39 by ports 43 and can be connected to a source of controlling fluid under pressure by way of passage 43. Where the device is to be employed as an automatic pressure reducer, passage 43 is connected by a separate pipe to a point in the low pressure system where it is desired to maintain a desired pressure.

At the lower end of the operating rod I! a light compression spring 44 can be provided to urge the diaphragm late 25 downwardly. Th lower end or this spring is shown seated upon the button 21, and the upper end is seated upon a guide 46 disposed within the lower end of the pipe 31.

As an aid in dissipating heat from the diaphragm mounting, a cylindrically shaped depending skirt 4'! can be provided. The upper intumed flange 48 of this skirt can be engaged below the upper clamping rings 34. Clrcumfere'ntially spaced slots 49 are provided in this skirt to permit passage of convection currents of air.

Connected to the lower mounting part 3| there is a fitting for the purpose of admitting or venting oii loading gas. A suitable construction for this fitting is shown in Figure 2. Briefly it consists of a body 52 having a threaded portion 53 for engaging with dome part 3|. Within the central opening 54 of the body there is a small check valve assembly 55. This assembly can consist of a small fitting 51 to which a suitable pressure pump can be applied, with the inner end of this fitting provided with a cylindrical extension 58, over which a resilient rubber tube 59 is seated. The main passage 6| through fitting 51.

communicates with the inner surface of sleeve 59 through a small port 52. When sufllcient pressure is applied to the exterior end of the fitting 51 tube 59 is expanded to permit the air to pass through port 52 into the passage 54. To vent ofi air or other gas the body 52 is threaded to accommodate the needle valve 6|]. By slightly opening this needle valve with respect to its seat 3, one can vent off a desired amount of compressed gas from the central passage 54. Body 52 is also shown provided with a threaded opening 64 for making connection to the pressure gauge 56;

Within the dome part 3| I normally provide a 7 quantity of liquid'or inelastic fluid 61, which can be any liquid which is stable at the operating temperatures employed, and which will have no corrosive or deleterious efieotupon the associated metal and rubber parts. One liquid which I have used with good results is glycerine. Fitting 5| is provided with a tube 68 which extends to a point above the surface of liquid 51, so that gas can be introduced into or vented from the space above the liquid;

Extending down into the body of liquid 61 there is a tube 53, the upper end of which is silver-soldered into an opening ll provided in the part 29 (Fig. 3).. Threaded within the upper end of this tubethere is. a small fitting 12, which forms a flow restricting orifice 13. It will 'mediately overlying the diaphragm. Likewise 1 this space is in direct communication with the beevident that tube as. together with the orifice fitting I2, serves to establish communication with the space between part 29 and the lower side or the diaphragm, and the main space 10 of the dome part 3|, at a point within the body of liquid 81. In place of the orificefitting 72, the

tube 63 can be made sufliciently small to provide the desired flow restriction. In order to insure flow of liquid into the space below the diaphragm, when the diaphragm flexes upwardly from a position in contact with part 29, the upper face of the latter is provided with one or more grooves 14 (Fig. 4) which connect with orifice I3. ing movements of the diaphragm, which necessarily occasion a change in the volumetric capacity or the space between the diaphragm and part 29, must be accompanied by a surging of the liquidathrough the tube 59 and the restricted oriflce Operation of the device described above can be outlined as follows: It will be assumed that inflow opening II is connected to a high pressure steam system, and that the outflow passage I2 is connected to piping and appliances forming a low pressure steam system. Also assume that the passage 43 is connected by an extended pipe to a point in the low pressure system where it is desired to maintain a substantially constant pressure. Because of dissipation of heat from the diaphragm mounting, by radiationand convection currents of air, a column of condensate is maintained within chamber 42 and within the passage 39, and the outflow pressure is exerted through this column of condensate, on the upper side of the diaphragm 24. At the time of installation of the device no gas pressure will exist within the dome part 3|. After installation and before usage, air under pressure is applied within chamber 10, through fitting 5|, until a pressure is attained comparable to the pressure desired upon the outflow side of the regulator. While pressure is thus being applied, any

small amount of air in tube 69 and in the space tain the pressure on the outflow side at the desired value. Variations in the outflow pressure transmitted to chamber 42, cause flexing of the diaphragm, to make corresponding compensating changes in the position of the valve member.

Although the loading pressure upon the diaphragm is maintained pneumatically, the restraint upon the diaphragm is hydraulic. Any flexing of the diaphragm must be accompanied by flow of liquid through tube 69 and orifice 13, with the result that relatively high restraining forces are imposed against rapid movements of the diaphragm. Therefore there is no tendency for rapid movements of the diaphragm to occur, and consequently a column of condensate is maintained at all times over the diaphragm,

and the diaphragm is not subject to overheating or to rapid fluttering.

Overheating of the diaphragm and its resultant disintegration is also minimized by the fact that its lower face is in contact with the liquid, rather than air. The liquid serves more effectively to conduct away heat, and serves to prevent oxidation of the type which tends to occur when rubber is in contact with air at elevated temperatures.

Flex- Another feature of this invention is that while it serves to efiectively restrain the diaphragm against rapid'flexing movement in response to outflow pressure variations, there is relative freedom from hunting action. Thus when a change in pressure occurs upon the outflow side, there is responsive flexing of the diaphragm toreposition. the valve member, but after the diaphragm is flexed to a position corresponding to the demand there is no continued hunting. Hunting is known to be undesirable as it tends to cause fluctuations in the outflow pressure having no specific relationship to the demand.

The body of liquid 61 can be introduced into the dome part 3|, as for example by removing plug I6, either at the time the regulator is assembled at the factory, or at the time of its installation and before it has been placed in use. The quantity of liquid should be ample to occupy the space between the diaphragm 24 and wall 29, when the diaphragm is flexed upwardly, plus a sufilcient excess to insure that the lower end of tube 69 is submerged at all times. .At the same time the quantity of liquid should not be so great as to provide an insuificient space in the dome part 3| for the trapped air under pressure. A substantial volume of trapped air is desirable so that flexing of the diaphragm does not cause appreciable changes in the pressure of the trapped air.

The size of the orifice 13 can vary in diflerent instances, depending upon various factors such as the conditions of operation, the size of the diaphragm, and the degree of restraint desired. For example where the regulator is designed for inflow steam pressures varying from 600 to 700 lbs. per square inch, and outflow pressures varying from 450 to 500 lbs., the orifice 13 can be of the order of from to of an inch, for diaphragms ranging from 3 to 8 inches in diameter.

Instead of utilizing a fixed or trapped quantity of compressed air in the'dome part 3|, it is possible to connect this dome part to a source of air at the desired pressure. In this connection it is possible to utilize an adjusting loading regulator for conveniently changing the regulator for diflerent outflow pressures, inthe manner disclosed and claimed in co-pending application Serial No. 308,622, filed Dec. 11, 1939.

I claim:

1. In a fluid flow controller, a valve body having inlet and outlet passages and a stationary valve seat, a valve member movable between open and closed positions with respect to the valve seat, a flexible diaphragm associated with the valve member and adapted when flexed between limiting positions to move the valve member between open and closed positions, means forming a fluid chamber on one side of the diaphragm and adapted to receive a controlling fluid of varying pressure, a loading dome embracing the other side of the diaphragm, a partition 'wall extend ing across said other side of the diaphragm and across that portion of the loading dome adjacent the diaphragm. said partition wall forming an enclosed space between it and the adjacent side of the diaphragm and a second enclosed space with the main part of the loading dome, the diaphragm being adapted to contact theadiacent face of the partition wall for closed position of the valve member, a body oi-iiquid occupying part but not inflow and outflow openings, a valve seat formed within the body, a valve member cooperating with the valve seat and movable in opposite directions between open and closed positions to control flow of steam through the body, a fluid pressure operated diaphragm, a mounting for said diaphragm disposed below the valve body, said mounting forming fluid chambers above and below said diaphragm, the chamber below the diaphragm being adapted to contain gas under pressure and the upper chamber being adapted to contain hot condensate, a wall extending across the lower side of the diaphragm and serving to isolate a closed space immediately below the diaphragm irom the remainder of the space formed below the diaphragm by said mounting, a body of liquid occupying part but not all of said last named space, a tube having its upper end communicating with the space immediately below the diaphragm and having its lower end extending into the body of liquid, said tube and substantially all of the space between the diaphragm and said Well being filled with liquid from the body whereby liquid is in constant contact with the diaphragm, and a flow restricting orifice serving to restrict flow of liquid through said tube.

3. In a fluid flow controller, a valve body having inlet and outlet passages and a stationary valve seat, a valve member movable between open and closed positions with respect to the valve seat, a flexible diaphragm located below the valve body and. connected to operate the valve member, the diaphragm when flexed between limiting positions serving to move the valve member to open and closed positions, means forming a fluid champressure, a loading dome embracing the lower side ofthe diaphragm, a partition wall extending across the lower side of the diaphragm and across that portion of the loading dome adjacent the diaphragm, said partition wall forming an enclosed space between the same and the adjacent lower side of the diaphragm and a second enclosed space with the main part of the loading dome, a body of liquid occupying the lower part of the second space, the remainder of the second space being adapted to receive gas under pressure, a tube having its upper end communicating with the first space and having its lower end extending into said body of liquid, a flow restricting orifice serving to restrict flow of liquid through said tube, and a second tube carried by the loading dome and having an inner open end communicating with the second space at a point near the central vertical axis of the same and above the level of the liquid. the other end of said tube being adapted to communicate with the ex- 

